Muffler



W. H. POWERS MUFFLER Filed Ndv. 28, 1955 April 26, 1960 INVENTOR. MQ/Zer 770W67-$ -BY jaw, J m

- n raF/vz/s MUFFLER Walter H. Powers, ilackson, Mich., assignor, by mesne assignments, to Walker Manufacturing Company, Racine, Wis., a corporation of Delaware Application November 28, 1955, Serial No. 549,423

3 Claims. (Cl. 181--,53)

This invention relates to mufllers and, in particular, to mufllers for silencing the exhaust gases of automotive type Vehicles, such as passenger cars and trucks.

H United States Patent M .It is the principal object of this invention to provide ing conduits within a mufiler will be disposed within chambers that are also used to attenuate sound.

The construction whereby the foregoing objects and features, among others, are carried into practice will be found in the accompanying drawings which show, as an illustration of the principles of the invention, a preferred embodiment thereof and in which:

Figure 1 is a longitudinal section through a muifier embodying the invention;

Fig. 2 is a cross section taken along the line 22 of Fig. 1;

Fig. 3 is a cross section taken along the line 3--3 of Fig. 1;

Fig. 4 is a cross section taken along the line 4-4 of Fig. l; and i Fig. 5 is a cross section taken along the line 55 of i Fig. 1. I

The muffier construction 1 shown in the drawings comprises a casing 3 which may be of any desired wall structure. It is preferably oval in cross section so as to best accommodate the three tubesconstituting a tri-fiow type mufller. The ends of the casing 3 areclosed by an inlet header 5 and an outlet header 7 which are interlocked in a rolled-over spiral joint 9 with the end sections of the shell, this being done after the various inside parts have been inserted and properly assembled in place. The headers 5 and 7 are illustrated as interchangeable and preferably include the double concavity 11 which in end elevation would appear as approximately circular.

Disposed within'the casing'3' is a subassembly 15. This includes the two partitions 17 and 19 which have flanges around their periphery that are turned toward the adjacent ends of the mufller so that the flanges may be spot welded to the casing 3 by spot welding apparatus located on the inside and the outside of the muflier prior to attachment of the heads 5 and 7. The partitions 17 and 19 have flanged aligned openings 21, 23, and 25 and spot welded to the flanges of these openings are, respectively, the inlet tube 27, the intermediate tube 29, and the outlet tube 31. Fitting on and around the tubes 29 and 31 are pancake assemblies (longitudinally split shells) 33 and 35, respectively, the construction of which is evident from Fig. 3. They consist of a pair of opposite identical halves which have flanges 37 that are spot welded together, the end portions 39 and the intermedi- 2,934,161 Patented Apr. 26, 1960 ate portions 41 of the sections being necked down to fit tightly around the outside surface of the tubes 29 and 31. The pancake assembly 33 provides the spit chambers (high frequency sound attenuating volumes) 43 while the pancake assembly 35 provides the spit chambers 45 surrounding the respective conduits 29 and 31. The partitions 17 and 19 along with the three tubes 27, 29, and 31 and the pancake assemblies 33 and 35 are all assembled and spot welded together as a subassembly 15 of the type disclosed and claimed in the aforementioned application.

According to the present invention, additional crossover split shell pancakes 47 and 49 are welded to the partitions 19 and 17, respectively, Fig. 1 showing only the bottom halves of the pancakes. The pancake 47 consists of a pair of identical halves with flanges 51 that are spot welded together. The pancake 47 provides passage 48 which has an inlet opening that fits over the flange opening 21 for conduit 27 and an outlet that fits over the flange 23 for conduit 29. End flanges 53 around the inlet and outlet openings and radial thereto are welded to the partition 19 so as to provide a gastight connection between the ends of the pipes 27 and 29 and the cross-over 47. It will be noted that the pancake assembly 47 is disposed within a chamber 55 that is formed in the space between the partition 19 and the end header 7.

At the other end the pancake assembly 49 is used to provide a cross-over conduit 56 connecting the outlet of tube 29 and the inlet of tube 31. As seen best in Figs. 1 and 5, this pancake assembly is comprised of identical complemental halves which are spot welded together along outside flanges 57 and at intermediate flange or web 59. It is spot welded to the partition 17 in a gastight connection by means of transversely extending flanges 61 which go around the entire circumference of the unit 49 at it inside end. The cross-over passage 56 is curved and circular and will cause gases to flow from the tube 29 toward the tube 31. However, communicating with the section of this passage immediately adjacent to the end of the tube 31 is a transversely extending circular cross section passage 63 which opens into a chamber 65 formed between the partition 17 and a partition 67 that is disposed within the casing 3 and which has an outwardly turned flange so that it can also be spot welded to the casing at assembly. The partition 67 has openings 69 therein which connect the chamber 65 with -,a chamber '71 between the inlet header 5- and the partition 67; It will be seen that the spaces 65 and 71 constitute a compound resonator chamber arrangement connected to tubes 29 and 31 through passage 63, the latter being shown in alignment with tube 31.

The subassembly 15 with the attached pancakes 49 and 47 is inserted as a unit in the casing 3 whereupon the flanges of the partitions 17 and 19 are spot welded to the casing in proper position. After this, the partition 67 along with an inlet tube 72 and another pancake assembly 73 as a subassembly is inserted and the partition 67 spot welded in place. The pancake assembly 73 is identical in all respects'to the pancakes 33 and 35 that have been described above. The pancake assembly is spot welded to the inwardly turned flange 75 in the partition 67. The inner end of the tube 72 i necked down and slides in the flared opening of the tube 27 in the assembly 15 as seen at 77. The outer end of the tube 72 may be spot welded to the outwardly turned flange 79 in the header 5 in a gastight connection.

At the outlet end. an outlet tube or bushing 81 is necked down and slides in the flared end of the tube 31 as seen at 83. The outlet bushing 81 is spot welded to the outwardly turned flange 87 on the outlet header 7.

The various tubes have apertures such as shown in the drawings which are identified by the reference numerals 89, it being understood that louvers or various other types of openings may be used in place of the round holes indicated.

Gas to be silenced enters the inlet pipe 72 and as it passes by the chambers 91 formed by the pancake assembly '73, certain of the high frequencies are attenuated. The gas then enters the tube 27 and it communicates through openings 89 with a relatively large volume spit chamber 93 formed Within the body of the casing 3 between the partitions 17 and 19. In leaving the tube 27 it is turned 180 degrees as it passes through the passage defined by the pancake 47 and into the intermediate conduit 29. In passing through the conduit 29 additional high frequency notes are attenuated in the spit chambers 43. Gas leaving the tube 29 enters the passage 56 in the pancake 49 where it can pass to the inlet end of the conduit 31. However, gas within the passage 56 or within the tube 31 communicates through the passage 63 with the resonator chambers 65 and 71 which is the sole avenue by which it can reach or escape from these chambers. Gas passing through the tube 31 will be silenced in the high frequency range of the additional spit chambers 455 and when it enters the outlet tube 81 relatively low frequency roughness will be silenced in the spit chamber 55.

It will be noted, in particular, that the cross-overs 47 and 49 are disposed within the chambers 55 and 65 and that the pancake assembly 73 is disposed within resonator chambers 65 and 71. This permits a substantial reduction in length of the over-all mufiier construction as compared with prior designs in which separate chambers were provided for the cross-over construction and in many cases for the spit chamber constructions. Nevertheless, many different silencing means are carried within the casing. It will also be evident that the pancake can be turned over if desired to align passage 63 with the outlet of tube 29.

While a preferred form of the invention has been shown in order to illustrate the principles thereof, it will be understood that various modifications can be made within the spirit and scope of the invention.

I claim:

1. In a muffler construction characterized by a short length, an oval casing having end headers, an inlet bushing in one header and an outlet bushing in the other header, three longitudinally spaced transverse partitions inside said casing and acting with said headers to define four chambers in said casing, three longitudinal tubes mounted on a pair of said partitions and disposed in the chamber defined by said pair of partitions, certain of said chambers being on opposite longitudinal sides of said just mentioned chamber, one of said three tube being joined to one of said bushings and extending through two other of said chambers and another of said tubes being joined to the other of said bushings and extending through the last of said chambers and having openings therein communicating with said last chamber, cross-over shells carried by said partitions respectively and serving to connect adjacent ends of said tubes to form a triflow gas pattern through the casing, said cross-over shells being located in the chambers on either side of said chamber defined by said pair of partitions, one of said cross-over shells being located in the innermost of said two other chambers and having a tuning neck formed therein opening into said chamber, means forming a tuning neck in the partition between said two other chambers, said tube extending through said two other chambers having openings in the portion thereof in said chambers, and a shell around said openings forming a closed chamber around said tube portion and extending through an opening in and mounted on the partition between said two other chambers, said tuning neck extending transversely of the length of the casing.

2. The invention set forth in claim 1 wherein said tuning neck cross-over shell is formed of complemental halves secured together along a midplane to define a pancake type crossover.

3. In a muffler construction characterized by a short length, an oval casing having end headers, an inlet bushing in one header and an outlet bushing in the other header, three longitudinally spaced transverse partitions inside said casing and acting with said headers to define four chambers in said casing, three longitudinal tubes mounted on a pair of said partitions and disposed in the chamber defined by said pair of partitions, certain of said chambers being on opposite longitudinal sides of said just mentioned chamber, one of said three tubes being joined to one of said bushings and extending through two other of said chambers and another of said tubes being joined to the other of said bushings and extending through the last of said chambers and having openings therein communicating with said last chamber, crossover shells carried by said partitions respectively and serving to connect adjacent ends of said tubes to form a tri-fiow gas pattern through the casing, said cross-over shells being located in the chambers on either side of said chamber defined by said pair of partitions, one of said cross-over shells being located in the innermost of said two other chambers and having a tuning neck formed therein opening into said chamber, said tube extending through said two other chambers having openings in the portion thereof in said chambers, means forming an opening in said partition between said two other chambers, and a shell around said openings forming a closed chamber around said tube portion, said tuning neck cross-over shell being formed of complemental halves secured together along a midplane to define a pancake type cross-over, the tuning neck therein being transverse to the length of the casing.

References Cited in the file of this patent UNITED STATES PATENTS 2,070,543 Cary et al. Feb. 9, 1937 2,115,113 MacKenzie et al. Apr. 26, 1938 2,151,470 Hollerith Mar. 21, 1939 2,182,945 Gunn Dec. 12, 1939 2,656,005 Cary Oct. 20, 1953 2,661,073 Deremer Dec. 1, 1953 

